Possibility of PD calibration on power transformers using UHF probes

Jahangir, Hamid; Akbari, Asghar; Werle, Peter; Szczechowski, Janusz

doi:10.1109/tdei.2017.006374

Cited by 26 publications

(13 citation statements)

References 8 publications

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“…In [89], the authors examined the effect of different PD types on UHF calibration in a power transformer whose circuit diagram is shown in Fig. 5.…”

Section: B Electromagnetic Detection Methodsmentioning

confidence: 99%

“…Six drain valves help to install different UHF probes at different locations. The authors in [89] introduced the best possible detection frequency range to measure the UHF signal concerning PD apparent charge. Also, they illustrated the big challenge to reduce calibration error due to active transformer parts thereby, it was inefficient to use the UHF probe.…”

Section: B Electromagnetic Detection Methodsmentioning

confidence: 99%

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Overview and Partial Discharge Analysis of Power Transformers: A Literature Review

2021

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“…In [89], the authors examined the effect of different PD types on UHF calibration in a power transformer whose circuit diagram is shown in Fig. 5.…”

Section: B Electromagnetic Detection Methodsmentioning

confidence: 99%

Section: B Electromagnetic Detection Methodsmentioning

confidence: 99%

Overview and Partial Discharge Analysis of Power Transformers: A Literature Review

2021

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“…It may be difficult to find a reasonable correlation from the UHF signal magnitude to the amount of charge in pC; however, if this relationship can be achieved, the sensitivity verification can be done on site via the UHF approach which overcomes the on-line performance issues associated with the IEC 60270 method [ 36 ]. Given that the UHF measurement in a power transformer is affected by many factors, including detection frequency range, defect type, physical internal barriers along with the characteristics of applied UHF sensor, the calibration is more problematic with a higher degree of uncertainty as compared to conventional measurement [ 73 ]. Therefore, the validity of the UHF method to estimate the severity of the PD activity is an issue requiring further investigations.…”

Section: Uhf Sensors In Partial Discharge Detectionmentioning

confidence: 99%

Application of UHF Sensors in Power System Equipment for Partial Discharge Detection: A Review

Chai

Phung

Mitchell³

2019

Sensors

101

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Condition monitoring of an operating apparatus is essential for lifespan assessment and maintenance planning in a power system. Electrical insulation is a critical aspect to be monitored, since it is susceptible to failure under high electrical stress. To avoid unexpected breakdowns, the level of partial discharge (PD) activity should be continuously monitored because PD occurrence can accelerate the aging process of insulation in high voltage equipment and result in catastrophic failure if the associated defects are not treated at an early stage. For on-site PD detection, the ultra-high frequency (UHF) method was employed in the field and showed its effectiveness as a detection technique. The main advantage of the UHF method is its immunity to external electromagnetic interference with a high signal-to-noise ratio, which is necessary for on-site monitoring. Considering the detection process, sensors play a critical role in capturing signals from PD sources and transmitting them onto the measurement system. In this paper, UHF sensors applied in PD detection were comprehensively reviewed. In particular, for power transformers, the effects of the physical structure on UHF signals and practical applications of UHF sensors including PD localization techniques were discussed. The aim of this review was to present state-of-the-art UHF sensors in PD detection and facilitate future improvements in the UHF method.

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“…This correlation is considered as being not possible in general, because the signal propagation of electrical measurement and UHF measurement inside a transformer is intrinsically unknown for both and, hence, not comparable. As a result, many publications conclude subsequently, that UHF calibration is not possible [32]. It is important to emphasis (again), that correlation and calibration represent two entirely independent issues and must not be mistaken.…”

Section: Comparison Of Electrical and Uhf Calibration Procedure-diffementioning

confidence: 99%

Calibration Proposal for UHF Partial Discharge Measurements at Power Transformers

Siegel¹,

Coenen

Beltle

et al. 2019

Energies

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The continuous, non-intermitted service of electrical grids relies on the reliability of their assets, e.g., power transformers. Local insulation defects can result in serve failures such as breakdowns with severe subsequent costs. The prevention of such events is crucial. Hence, partial discharge (PD) activity at power transformers is evaluated directly in the factory before shipment. Additionally, PD activity can be monitored during service using the ultra-high frequency (UHF) method. In this contribution, a calibration procedure is proposed for the UHF method. The calibration process is required to ensure both, reproducibility and comparability of UHF measurements: Only a calibrated UHF measurement procedure can be introduced supplementary to IEC 60270 in acceptance tests of power transformers. The proposed calibration method considers two factors: The influence of the UHF-antenna's sensitivity and the PD recorder characteristics including accessories such as cable damping, pre-amplifier, etc. The former is addressed by a characterization of UHF sensors using the standard antenna factor (AF) in a gigahertz transverse electromagnetic (GTEM) cell. The PD recorder's influence is corrected by using a defined, invariable test signal as reference for all recording devices. A practical evaluation of the proposed calibration procedure is performed in a laboratory setup using different UHF recording devices and UHF sensors using artificial PD signals and real voltage-driven PD sources.

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Possibility of PD calibration on power transformers using UHF probes

Cited by 26 publications

References 8 publications

Overview and Partial Discharge Analysis of Power Transformers: A Literature Review

Overview and Partial Discharge Analysis of Power Transformers: A Literature Review

Application of UHF Sensors in Power System Equipment for Partial Discharge Detection: A Review

Calibration Proposal for UHF Partial Discharge Measurements at Power Transformers

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